Heat Transfer Fluid Loop Control for Cryogenic Fuel Heating
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Solution Overview
Problem
Existing fuel conditioning systems for aircraft turbomachines face challenges in efficiently heating cryogenic fuel without increasing the flow rate of the heat transfer fluid, leading to significant mass and size of piping, limited aerothermal performance, and high energy consumption.
Innovation Solution
A two-stage heating system for the heat transfer fluid, utilizing multiple heat exchangers and a regenerative exchanger to optimize temperature control, allowing the fluid to exceed maximum operating temperatures without increasing flow rate, thereby reducing piping mass and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the flow rate of the heat transfer fluid is increased to limit maximum temperature, then the temperature control is improved, but the mass and size of piping increases significantly
Solution Approach 1:
The system divides the heating process into multiple stages using separate heat exchangers (first engine heat exchanger, second engine heat exchanger, first tank heat exchanger, second tank heat exchanger) arranged in series. Each heat exchanger performs a portion of the heating task, allowing the heat transfer fluid to operate at lower flow rates while achieving the required temperature control through cumulative heat transfer.
2Temperature
If the flow rate of the heat transfer fluid is increased to limit maximum temperature, then the temperature control is improved, but the aerothermal performance of heat exchangers deteriorates
Solution Approach 1:
The heating process is segmented across multiple heat exchangers, allowing each exchanger to operate within optimal flow rate ranges for maximum aerothermal efficiency. The series arrangement ensures that the heat transfer fluid passes through each exchanger sequentially, maximizing heat transfer effectiveness at reduced flow rates.
3Temperature
If the flow rate of the heat transfer fluid is increased to limit maximum temperature, then the temperature control is improved, but the electrical consumption of the mechanical pump increases
Solution Approach 1:
The system segments the temperature control function across multiple heat exchangers operating in series, enabling effective heat transfer at lower fluid flow rates. This reduces the work required by the mechanical pump, thereby decreasing electrical consumption while maintaining adequate temperature control.
4Productivity
If the temperature of the heat transfer fluid exceeds maximum operating temperature, then the heating efficiency is improved, but the aircraft structure is damaged
Solution Approach 1:
The system uses multiple heat exchangers arranged in series to distribute the heating function across several stages. This segmentation allows the heat transfer fluid to be heated progressively, preventing any single heat exchanger from causing excessive temperature rise that could damage the aircraft structure, while collectively achieving the required heating efficiency.
Solution Approach 2:
The heat transfer fluid acts as an intermediary carrier that transfers thermal energy from hot sources to the fuel to be heated. By using this intermediate fluid in a controlled circulation loop with multiple heat exchangers, the system efficiently transfers heat without requiring direct contact between high-temperature sources and the aircraft structure, preventing thermal damage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively heats the fuel to optimal injection temperatures while minimizing piping size and weight, optimizing aerothermal performance, and reducing mechanical pump energy consumption.
Implementation Method 1
a temperature control system 101 of a heat transfer fluid F which provides calories to the fuel flow Qc in order to warm it
Implementation Method 2
the heat transfer fluid F extracts heat from available hot sources Cm on board the aircraft via an engine heat exchanger 104
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a system (1) for controlling the temperature of a heat transfer fluid (F) configured to transfer heat to a fluid to be heated (Q) originating from a cryogenic tank (R), the control system (1) comprising: a loop (2) for circulating the heat transfer fluid (F), comprising an engine branch (21) and a tank branch (22); a first engine heat exchanger (41), configured to heat the heat transfer fluid (F) to a second temperature (T2) above a maximum operating temperature (Tmax); a mechanical pump (3) configured to circulate the heat transfer fluid (F) in the circulation loop (2), such that, in a second engine heat exchanger (42), a first part of the heat is transferred from the heat transfer fluid (F) to the fluid to be heated (Q) and the heat transfer fluid (F) is cooled to a third temperature (T3) below the maximum operating temperature (Tmax), before it leaves the engine enclosure (EN-M).